Ink jet recording systems have recently attracted increasing interest since they can conduct high speed recording with negligible noise using so-called common paper with no particular requirement for fixing.
An ink jet recording head to be applied for the ink jet recording system is generally provided with minute ink discharging outlets (orifices), ink pathways and an ink discharging energy action portion disposed at a part of the ink pathways.
Hitherto, for the fabrication of such an ink jet recording head, there have been proposed various methods, for example, a method of forming minute grooves on glass or metal plate by cutting or etching and, subsequently, joining the grooved plate with another appropriate plate to form ink pathways.
However, for known ink jet recording heads manufactured by known methods, there are problems that the inner wall surface of the ink pathways formed by way of cutting is apt to be roughened excessively or distortion is likely to occur on the ink pathways due to the differences in the etching rate, and because of this, it is difficult to provide ink pathways of uniform flow channel resistance, thereby causing variations in the ink discharging characteristic. In addition, it also involves drawbacks that the plate tends to suffer from chipping or cracking upon cutting thereby reducing the production yield. Further, the etching fabrication requires a lot of production steps undesirably increasing production costs. Furthermore, there are other problems in common with the known methods: for example, when the engraved plate formed with ink pathway grooves and a substrate on which energy generating elements (hereinafter simply referred to as active elements) such as piezoelectric elements, heat generating elements, etc. for generating energy to be utilized for jetting out the ink are laminated to each other, the alignment between them is difficult to achieve when they are mass produced.
As an ink jet recording head having a constitution capable of overcoming these problems, there has been proposed an improved ink jet recording head, for example, in Japanese Patent Laid-Open No. Sho 58-43876 in which ink pathway walls comprising a cured film of a photosensitive resin composition are formed and, subsequently, a lid is disposed to the pathway walls. The ink jet recording head manufactured by utilizing the photosensitive resin composition is excellent in overcoming the problems of the ink jet recording head in the prior art, i.e., prior finishing accuracy for the ink pathways, complicated production steps and low production yields.
By its way, in the ink jet recording heads utilizing the photosensitive resin, solid film material mainly comprising an acrylic resin has mainly been used in view of its cost and its productivity characteristics. However, the ink jet recording head in which the ink pathway walls are formed by using the photosensitive resin composition mainly comprising the acrylic resin involves several drawbacks for example, as the recording time is remarkably increased, the ink discharge from the orifices, may sometimes be interrupted the accuracy of discharged ink droplets is reduced when they hit recording medium (such as paper as described above), etc.
In view of the above, there is a need for an ink jet recording head having improved hitting accuracy and the discharging durability capable of easily ensuring high reliability.